Nanban

Nanban (南蛮) is an old Japanese term meaning "southern barbarian(s)", referred to the Europeans who came to visit Japan around the 16th to 17th century. Most of them sailed to Japan from the south, and they didn't know the Japanese cultures and manners, so they were called "southern barbarians".

It can be compared to the term "Gaijin" in modern Japanese language.

Yamada: "Hey look at that gaijin eating ramen with a fork & a spoon, what a moron.
Tanaka: "Yeah, he's a fucking nanban"